Clem Miller in Autumn Gwen Heistand In the autumn we see waterfowl and shorebirds returning from points north to spend their winters feasting on our local bounty. Some good bird things to talk about at Clem Miller are: resource partitioning, eclipse plumage (molting), and migration. Bird migration can lead to discussions about biomes and geography. In addition, it’s a great place to talk about our local geology. Resource Partitioning: Shorebirds: Here are a couple different pictures of resource partitioning among shorebirds. The different sizes, shapes, and lengths of shorebird bills allow then access to different mud critters. (a different view w/ similar birds to ours) In addition, although both Western Sandpipers and Semipalmated Plovers snatch invertebrates from the surface or near the surface, they partition resources using different search patterns. (from Marine Biology by Castro & Huber) 1 Clem Miller in Autumn Gwen Heistand 9/6/2005 Who are the birds eating? There are all sorts of cool things that live in the mud. If kids want to know who the birds are eating, here are a few pictures of some of the critters. Each one of these animals has a unique and interesting life history in its own right. Many of the burrowing animals host guests (or commensals) in their burrows. That is another topic entirely! Capitella (polychaete worm) Letpochelia (small crustacean) Arenicola (lug worm) Polydora Nereis Corophium (polychaete worm) (Polychaete worm) (small crustacean: amphipod) 2 Clem Miller in Autumn Gwen Heistand 9/6/2005 Ducks partition resources too. Most of us have learned that there are dabblers and there are divers. (See if you can get the kids to figure out which ones are which). However, the partitioning doesn’t stop there. Dabbling ducks dabble at slightly different water depths. They also have different tongues and bills which allow them to sieve different sized particles out of the water. Northern Shovelers forage by skimming surface water and mud. They have a wide, spatulate bill and one of the more amazing tongues on the planet, adapted to be able to strain fine particles. Mallard bills are adapted for a generalist diet of straining invertebrates or picking up marsh seeds and agricultural grains. Green-winged Teals strain almost microscopic invertebrates from the mud. Among diving ducks: Mergansers have long, serrated bills for holding onto fish and invertebrates. Surf scoters’ bills are stout and firm and used to pull shellfish from rocks underwater. Dabblers tend towards smaller feet and their legs are further forward than diving ducks. Dabblers skim the surface or feed in shallow areas typically. Dabblers have larger wings relative to their body weight and fly slowly. This enables them to land on and take off from small areas of water. Divers have large feet and short legs situated far back on their bodies which are used to propel them through the water. Divers have smaller wings relative to body weight, fly faster, and need more open water to take off. Dabblers, Divers, and Ducks That Dive that you may see at Clem Miller… Dabblers (Anas) Divers & Stiff-tailed Divers Ducks that Dive Green-winged Teal (Aythya; Oxyura) (But that are not usually referred Mallard Greater Scaup to as "Divers"; often called "Sea Northern Pintail Lesser Scaup Ducks") Scoters (Melanitta) Cinnamon Teal Ruddy Duck Goldeneyes (Bucephala) Northern Shoveler Canvasback Bufflehead (Bucephala) Gadwall Redhead Mergansers ( Mergus, Lophodytes) American Wigeon Ring-necked Duck Eurasian Wigeon 3 Clem Miller in Autumn Gwen Heistand 9/6/2005 Eclipse Plumage: It is often still possible to observe waterfowl in eclipse plumage at the beginning of the fall hiking season. What does this mean? After breeding is complete, males of most duck species molt into a dull, cryptic plumage often termed eclipse plumage. During this molt, male ducks molt their main flight feathers as well. Duller than normal plumage makes sense if you are a duck without fully working flight feathers and want to keep well hidden from predators. (One of my first calls at BLP was a man very disturbed because all of the male mallards had disappeared at Las Galinas sewage ponds!) The return to breeding (alternate) plumage varies in species and individuals of each species, lasting usually from between 1 to 3 months. I used to wonder why the molt to breeding plumage happened in such quick succession. It turns out that most ducks form pair bonds during the winter so the males need their breeding colors. Blue-winged Teals and Northern Shovelers may retain the eclipse plumage well into the winter. Molting .. in general What is this whole molting thing about? The fact that feathers get worn and need to be replaced is pretty cool. The process of shedding and replacing worn feathers is called molting. The feather coats worn in between molts are called plumages. Most people are familiar with winter, summer, nuptial and breeding plumages. This gets confusing. Humphrey & Parkes proposed a different naming convention in 1959. This terminology is being used more and more. If you read Sibley, you will notice plumages referred to basic and alternate Adult birds undergo a prebasic molt into a basic plumage just after breeding season. Ducks’ molt into eclipse plumage is a prebasic molt. (For a good chart describing the difference between traditional plumage names and Humphrey & Parkes see page 108 of Manual of Ornithology by Proctor & Lynch in the BLP Library Reference section.) Birds have different feather tracts (pterylae). A molt may include one, some, or all of these feather tracts. For a good diagram of all these feather tracts, see pages 100-101 of Manual of Ornithology by Proctor & Lynch.) One interesting thing that has been discovered recently … Herons and Egrets begin growing their nuptial plumes almost immediately after they have been molted. It turns out that these are very slow growing feathers and reach their full size in time for the next alternate plumage cycle. 4 Clem Miller in Autumn Gwen Heistand 9/6/2005 Migration: It is possible to talk about migration up at Clem Miller. Where have the birds we see in the fall returned from? A lot of kids have seen Winged Migration. Even for those who haven’t it is an interesting geography lesson to connect where the birds are with where they have been. These birds travel to completely different biomes from ours to breed and then come back. Not only does Bolinas Lagoon act as an overwintering place for birds, it is also a fueling stop for migrating birds. Range maps in bird guides are a great place to spend a little bit of time talking about geography. Here’s where some of the birds we see at Clem Miller go to breed. Bird Breeding locations Western Sandpiper sedge-dwarf shrub tundra: north and west coasts of Alaska Least Sandpiper mossy or wet grassy tundra: most of Alaska except extreme north and most of northern Canada Semipalmated Plover sandy habitat, grassy or mossy tundra: Alaska & northern Canada Whimbrel sedge meadows, bogs, tundra, heath: Alaska, around Hudson Bay Long-billed Curlew prairies and grassy meadows near water: inland in western states and southern central Canada Marbled Godwit shortgrass prairie, pastures, marshes, flooded plains: south/central Canada, north central US Long-billed Dowitcher grass tundra, wet meadows: northern Alaska Short-billed Dowitcher grass or moss tundra, wet meadows, bogs in boreal forest: southern Alaska and northern Canada Greater Yellowlegs muskeg & tundra: Alaska & Northern Canada Lesser Yellowlegs tundra, muskeg, wooland clearings, burned areas: Killdeer fields, meadows, pastures, mudflats, freshwater margins (here year-round) Willet Marshy lake margins and adjacent uplands, slat marshes, intertidal zone: inland in western states and southern central Canada American Avocet marshes, mudflats, ponds, alkaline lakes, estuaries: central/west-central use and southern Canada Forster’s Tern freshwater & saltwater marshes, marsh borders of ponds & lakes: inland Caspian Tern flat sand or gravel beaches, shell banks, occasionally marshes: inland Gadwall freshwater marshes: southern Alaska, north-central US, south-central Canada Northern Pintail grassland, cultivated field, tundra, sandy flat, island in boreal forest, lake, marsh, pond: north-central US, Canada, Alaska Northern Shoveler freshwater shallows, esp. muddy, sluggish habitats and surrounding marsh, wet prairie meadows: north-central US, western Canada, Alaska American Wigeon marshes, freshwater areas with exposed shorelines: north-central US, Canada, Alaska Mallard here year-round (ducklings often on Parson’s Pond) Green-Winged Teal densely vegetated inland freshwater lake, marsh, pond, pool, shallow stream: north- central US, Canada, Alaska Cinnamon Teal alkaline wetland in arid areas, shallow lake margin with emergent vegetation, lagoon, slough, sluggish stream, marsh: just inland Surf Scoter bogs, ponds or sluggish streams in brushy/forested habitats: Alaska, northern Canada Greater Scaup ponds and small lakes in forested or open tundra and n. border of taiga, islands in large taiga lakes: Alaska (except northern), northern Canada to Hudson Bay Lesser Scaup upland areas near pond or small lake, marsh, prairie potholes: north-central US, western Canada, central-eastern Alaska Common Goldeneye ponds, lakes, rivers, coastal bays, wooded marshy habitat: western Canada, central- eastern Alaska Bufflehead mixed conifer-deciduous woodland near lake or pond: western–central Canada, central-eastern Alaska Ruddy Duck densely vegetated freshwater marsh: inland – west-central US, central Canada Red-breasted Merganser Rivers, ponds, lakes, coasts, small islands of inland waters w/ low shrubby vegetation: Alaska, northern Canada 5 Clem Miller in Autumn Gwen Heistand 9/6/2005 There are some cool words associated with where birds breed … Tundra: is the coldest of all the biomes. Tundra comes from the Finnish word tunturia, meaning treeless plain. Soil is formed slowly. A layer of permanently frozen subsoil called permafrost exists, consisting mostly of gravel and finer material. Taiga (Boreal forest): Taiga is Russian for forest; largest biome in the world.